The present invention relates to an apparatus for tracing of electrical conductors where the path of the conductors to be traced is not readily observable due to either surrounding structure or the conductors"" disposition among many conductors of similar appearance. More particularly, this invention pertains to a tracing apparatus which combines a number of features to simplify use of the device.
In electrical installations, a number of electrical conductors are frequently routed through structures which hide the conductors from view. Examples are readily found in the average home, where telephone, cable television, and electrical wiring is generally located behind the wall, where it does not disrupt the appearance of the home, and where interaction between the wiring and the residents of the home is minimized. Similarly, in industrial installations, electrical wiring is frequently bundled and confined in an out of the way location, where accidental intervention with the wiring cannot occur.
In such installations, individual conductors can, therefore, be difficult to test, both because the tester cannot readily see the conductor, and because a specific conductor is difficult to isolate in a large number of conductors having a similar appearance. In these situations, the route of a specific conductor cannot be readily ascertained by visual tracing.
Because of the difficulty of tracing wires in walls or other conduits, or in a large bundle of similar wires, line or wire tracing devices have been developed. Wire tracing devices generally comprise a transmitter for transmitting an electromagnetic signal along a wire to be tested, and a receiver for wirelessly detecting the signal at another location in the wire. The electromagnetic signal is preferably a distinct modulated signal in the audio range. The receiver acts as an antenna, receiving and supplying the audio signal to provide an audio signal, the strength of which varies depending on the distance of the receiver from the wire carrying the audio can signal. Preferably, the receiver also includes a light emitting diode, which is lit to indicate a detected signal. Like the audio signal, the intensity of the light preferably increases as the receiver approaches an active wire.
The transmitter device is preferably stationary, and is electrically coupled directly to the wire to be tested. Typically, the transmitter comprises a circuit powered by a relatively large nine volt D cell battery, and the amplitude of signals produced by the battery are limited to nine volts. Furthermore, the nine volt power supply must supply a relatively large level of current to provide sufficient signal for detection.
The receiver device is a moveable, hand-held device, which can be moved along the outside of a wall or conduit to detect the transmitted signal, thereby providing an indication both of where the wire is routed and whether electrical continuity exists in the wire.
Wire testing and tracing devices, therefore, generally comprise a number of components. As noted above, the test unit itself comprises both a transmitter device and a handheld receiver, where the transmitter device must be relatively large to accommodate the nine volt battery power source. To trace wires in, for example, a home, a number of connectors are also required. For example, in a home inspection, a tester may need to test telephone, cable television, and AC voltage connectors. Although typical connectors such as alligator clips can be used for such testing, these devices generally require cutting and stripping of wires. Therefore, testers generally require specific phone jack, coaxial cable, and a straight blade AC electrical connectors which can be connected directly to existing wires without the need for stripping or cutting conductors. Furthermore, because the current levels supplied by the nine volt battery are high, spare batteries are often required. Because of the size of the components, as well as the large number of both components and connectors required, typical wire tracing devices, therefore, must be carried in a bag or carrying case.
Carrying cases and bags, however, can be problematic for the electrician or technician in the testing environment. The tracing of wires, for example, is generally only the first step in an electrical test. A technician or electrician therefore often requires a number of additional testing devices including voltmeters, current detecting devices, and other electrical testing equipment. The need for a bag or carrying case for each individual piece of equipment can cause significant inconvenience when all of the equipment must be carried by a single user. Furthermore, when a plurality of connectors and testing devices are maintained in a bag or carrying case, required parts of the testing equipment are frequently lost. Such equipment, for example, is frequently stored in a pocket or with another piece of test equipment rather than returned to the appropriate bag after testing. Such equipment is also frequently xe2x80x9cborrowedxe2x80x9d for another application and not returned. Furthermore, loose connectors and other equipment is frequently left behind when the testing is completed.
There remains a need, therefore, for a wire tracing device which simplifies the use and storage of wire tracing equipment.
The present invention is a wire tracing or electrical circuit tracing device which provides a transmitter, receiver, and a plurality of connectors in a single, compact, easy-to-use, easy-to-transport package.
To decrease the size of the device, the transmitter circuit is designed to operate on a low voltage supply, and can be operated with small triple A batteries, as opposed to the nine volt battery required in prior art devices. The transmitter is preferably operated on a three volt supply, which is amplified by a step up transformer to provide an operating voltage of approximately 20 volts, thereby providing a more robust signal than prior art devices. A small, inexpensive microcontroller controls and generates the signal, and also provides a sleep function, wherein the transmitter is automatically turned off after a predetermined operation time.
The transmitter circuitry of the wire tracing device is enclosed in a multi-functional housing. The housing is formed to include a pocket dimensioned to hold the receiver, thereby providing a location for storing the individual parts of the wire tracing device in a single package without the need for an external case or bag. Furthermore, a clip is coupled to the back of the housing in such a way that the transmitter can be snap fit onto a belt or other carrying device in order to eliminate the need to separately carry the wire tracer. The housing of the transmitter in effect provides a xe2x80x9cholsterxe2x80x9d for storing and transporting the wire tracing device.
To further simplify the use of the device, the housing of the transmitter section includes a storage rack designed to hold a plurality of common electrical connectors. The connectors can, for example, include a phone jack, a coaxial connector, and a male straight blade connector, each of which can be snap fit into the rack, where the connector is held in place during transportation.
Each of the connectors is preferably electrically coupled to the internal transmitter circuitry such that, when a test is required, a user need only connect the appropriate connector to a matching socket, and then activate the receiver to trace the line. Because the connectors are pre-wired to the testing device, the connectors cannot be lost or misplaced. Furthermore, the connectors provide easy access to a number of common connections, without the need for cutting or stripping wires.
Preferably, the storage rack and associated electrical connectors are coupled to the storage compartment which can be closed by shutting a lid. The lid is preferably hinged, and can include one or more latching devices for holding the lid in a closed position when the wire tracing device is not in use.
These and other objects and advantages of the invention will be apparent from the detailed description and drawings.